This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 9 |
| 3 | 43 |
| 4 | 196 |
| 5 | 882 |
| 6 | 3970 |
| 7 | 17887 |
| 8 | 80608 |
| 9 | 363254 |
| 10 | 1636944 |
| 11 | 7376591 |
| 12 | 33241289 |
| 13 | 149795989 |
| 14 | 675029164 |
| 15 | 3041899638 |
| 16 | 13707783053 |
| 17 | 61771701389 |
| 18 | 278363253873 |
| 19 | 1254394801761 |
| 20 | 5652708454881 |
| 21 | 25472931513057 |
| 22 | 114789263420590 |
| 23 | 517277526141329 |
| 24 | 2331019740675071 |